Young people leaving the care system in Wales will no longer pay council tax under legal changes due to come into force in April, ministers have said.About a third of Wales' 22 local councils already exempt care leavers from the tax, some until the age of 21 and others to 25.Charities had called on Welsh ministers to end a "postcode lottery" over whether they pay council tax.All care leavers under 25 will now get the help, under new legislation.